The answer to this is 65.
Remember that the angles opposite of each other equal to 180. So a+c=180 and b+d=180.
First, we solve for x. Since we know that b and d equal to 180, we subtract 148 from 180.
180-148=32. x=32.
Then we plug that in the expression for angle a.
2x+1 becomes 2(32)+1
2*32=64
64+1=65.
a=65
